黑龙江省农田土壤冻融过程及生境健康调控机理研究

黑龙江省特有的春季融雪型农田涝渍灾害导致苗期作物“烂根腐根”现象频发，严重威胁粮食产能提升与农业绿色发展。为破解黑龙江省春季作物生境健康调控技术瓶颈，将大气、积雪、冻融土壤视为一个作物依存连续体，对其行为特征及调控模式进行整合研究。首先模拟不同气候变化情景下农田土壤冻融变化过程，解析活动层水热循环物理机制及其水文效应；其次分析融雪期农田积雪物理特征参数变化规律，揭示积雪融水过程物理机制，识别不同作物承灾体对孕灾环境的响应关系，率定融雪型涝渍灾害发生阈值；然后建立大气-积雪-冻融土壤连续体污染物迁移模型，剖析农田冻融土壤水盐碳氮循环耦合互馈关系，阐释农田土壤冻融及其伴生过程的生态环境影响效应；最后设定不同调控方案，阐明农田土壤冻融期作物生境健康恢复机理，确定其最佳调控模式。研究成果可为缓解寒区春季涝渍灾害影响、合理利用冻土水-融雪水资源、保障农业水土环境健康与粮食安全提供重大理论与技术支撑。

The special farmland waterlogging disaster of spring snowmelting in Heilongjiang province leads to the frequent occurrence of rotten root phenomenon of crops in seedling stage, which seriously threatens the improvement of grain production capacity and the green development of agriculture. To solve the technical bottleneck of crop habitat health regulation in spring in Heilongjiang Province, the atmosphere, snow and frozen thawed soil are regarded as a dependent continuum of crops, and their behavior characteristics and regulation modes are studied. Firstly, simulate the soil freezing-thawing process under different climate change scenarios, analyze the physical mechanism of water and heat cycle in the active layer and its hydrological effect; secondly, analyze the change law of the physical characteristics parameters of snow cover in farmland during the snow melting period, reveal the physical mechanism of snow melting process, and identify the disaster bearing bodies of different crops, analyze the response relationship of disaster pregnant environment, the threshold value of snow melting waterlogging disaster is determined; then, the pollutant transport model of air snow freezing soil continuum is established, and the coupling and mutual feed relationship of water, salt, carbon and nitrogen of farmland freezing-thawing soil is analyzed to explain the ecological environment effect of farmland soil freezing-thawing and its associated process; finally, different control schemes are set to clarify the crops in farmland soil freezing-thawing period. The mechanism of habitat health restoration and the best regulation mode are determined. The results can provide important theoretical and technical support for alleviating the impact of spring waterlogging disaster in cold regions, rationally using frozen soil water and snowmelting water resources, and ensuring the health of agricultural soil and water environment and food security.